The Galileo planet Jupiter space probe, launched aboard Space Shuttle Atlantis October 18, 1989, was released from Galileo July 13, 1996 and entered Jupiter's atmosphere December 7, 1997.
It is the first manmade spacecraft to enter the atmosphere of a planet and send back data.
By the end of 1999, the spacecraft has completed more than four years of orbiting Jupiter, collecting pictures and data, allowing the scientific community to develop valuable and surprising new insights into the formation and evolution of our solar system and the origins of life within it.
The journey was a circuitous route dictated by power limitations at its sendoff, the failure of the main antenna to unfurl, erratic behavior of a tape recorder, and temporary shutdown of spacecraft instruments due to radiation zappings from Jupiter's radiation belts.
Nevertheless, Galileo achieved 70% of its scientific goals during its $1.5 million primary mission throughout 1997.
Its subsequent success in gathering data about Jupiter's four large moons - Ganymede, Europa, Callista, and IO - prompted an extension of the mission.
The Galileo space probe indicated Jupiter formed as much as 10 times further from the sun than it is now, had wide variations in radiation levels, 400 mile winds, extremely high temperatures with constantly stormy weather generated by heat from nitrogen sources deep in the planet.
The large moons have the highest temperatures in the solar system, many active volcanoes, and may have liquid oceans deep beneath their frozen surface, which possibly could support primitive organisms.
